package com.xjj.homework.w01;

public class M0641DesignCircularDeque {

    class MyCircularDeque {

        int[] arr;

        int front;

        int rear;

        int capacity;

        /**
         * Initialize your data structure here. Set the size of the deque to be k.
         */
        public MyCircularDeque(int k) {
            capacity = k + 1;
            // 满空状态分离
            arr = new int[capacity];
        }

        /**
         * Adds an item at the front of Deque. Return true if the operation is successful.
         */
        public boolean insertFront(int value) {
            if (isFull()) {
                return false;
            }
            // 头向前
            front = (front + capacity - 1) % capacity;
            arr[front] = value;
            return true;
        }

        /**
         * Adds an item at the rear of Deque. Return true if the operation is successful.
         */
        public boolean insertLast(int value) {
            if (isFull()) {
                return false;
            }
            // 尾向后
            arr[rear] = value;
            rear = (rear + 1) % capacity;
            return true;
        }

        /**
         * Deletes an item from the front of Deque. Return true if the operation is successful.
         */
        public boolean deleteFront() {
            if (isEmpty()) {
                return false;
            }
            // 删头则头向后
            front = (front + 1) % capacity;
            return true;
        }

        /**
         * Deletes an item from the rear of Deque. Return true if the operation is successful.
         */
        public boolean deleteLast() {
            if (isEmpty()) {
                return false;
            }
            // 删尾则尾向前
            rear = (rear + capacity - 1) % capacity;
            return true;
        }

        /**
         * Get the front item from the deque.
         */
        public int getFront() {
            if (isEmpty()) {
                return -1;
            }
            return arr[front];
        }

        /**
         * Get the last item from the deque.
         */
        public int getRear() {
            if (isEmpty()) {
                return -1;
            }
            // 上个数
            return arr[(rear - 1 + capacity) % capacity];
        }

        /**
         * Checks whether the circular deque is empty or not.
         */
        public boolean isEmpty() {
            return rear == front;
        }

        /**
         * Checks whether the circular deque is full or not.
         */
        public boolean isFull() {
            return (rear + 1) % capacity == front;
        }
    }

/**
 * Your MyCircularDeque object will be instantiated and called as such:
 * MyCircularDeque obj = new MyCircularDeque(k);
 * boolean param_1 = obj.insertFront(value);
 * boolean param_2 = obj.insertLast(value);
 * boolean param_3 = obj.deleteFront();
 * boolean param_4 = obj.deleteLast();
 * int param_5 = obj.getFront();
 * int param_6 = obj.getRear();
 * boolean param_7 = obj.isEmpty();
 * boolean param_8 = obj.isFull();
 */

}
